Method of making a bushing



Ap 1946- w. c. SHRIVER, JR 2,397,626

I METHOD OF MAKING A BUSHING Filed Oct. 12, 1942 9 7 e m5 0 [a Z n M 7.. a a a. J J i l1 ..%0, N r j 2\ 2 m M m a casing I6 is enlarged at its lower end it to receive gear "I, said casing having'a contour which fits quantity of the material mentioned above for forming the bushing, preferably a thermosetting plastic and which is designated as 2, is poured into opening it and-will occupy substantially the space indicated in Fig. 2. Following the insertion of the material into opening ll, mold casing 16 is lowered and the force I! is likewise lowered. Heat is then applied to the assembly including the casing IS, the force II, the gear II, the bed 15 and the material 24 for softening the material whereby the force moves through the material and forces ,it

upwardly and sidewardly against the wall of the,

aperture It. It will be observed that during the movement of force I! into the gear, excess material is given an opportunity to escape into an annular chamber 23 formed by shoulder 22 in force IT. The assembly is heated further, if the mate 30 The method of forming a bushing in a bore in rial 24 is thermosetting as is-preferable, and the assembly is allowed to cool in order to cause the material to set and when the material is sufllciently solidified to retain its shape, force I1 is raised, followed, by the mold easing, leaving the gear ill with a. bushing of plastic materialin place in the opening I. ground or otherwise suitably finished to size (18- pending upon the type of filler used in the plasticmaterial. Y

It will be observed that in the process above described, the gear itself constituted the cavity of the mold and that the bushing was formed directly against the inner surface of the gear so that when the bushing was finished a completely assembled gear and bushing were obtained. This represents a substantial economy in the formation of such gears since, were the bushing to be formed separately and then inserted as an entity into the gear, a number of additional steps and operations would be required in order to produce a finished gear. In addition it would be dimcult to insert the bush-,

ing into the gear and apply a suillcient force to obtain the requisite frictional between the bushing and gear without damaging the bushi118 itself since the material of the bushingdoes not withstand this type of working very well.

when the bushing is formed directly in the gear itself, however, as in accordance with this invention, all forcing of the bushing intothe gear is of course eliminated and furthermore the formation 1 0 ance to relative rotation than would be possible were the two formed separately and then united. The coefficient of friction of the bushings may be varied by varying the relative quantities of the constituents of the bushing forming material, and

it will be apparent that bushings having difierent coeflicients of friction may be manufactured one diiferent coeflicient of friction.

It is understood that the foregoing description is merelyillustrative of a preferred embodiment of the invention, particularly as to the machine element to which the invention may be applied 25 and the specific composition of the bushing material. The scope'of this invention therefore should not be limited to the embodiment illustrated but should be determined b the appended claim.

I claim: l

the hub of a machine element, said bore being open at both ends and being adapted to receive a shaft so that the machine element'and bushing may rotate on the shaft, which method comprises I, placing the machine element on its side on a flat The bushing may then be a bed so that the latter closes one end of said bore, introducing into said bore a quantity of fusible material in powder. form, introducing into said 40 bore a plunger which is smaller in diameter than said bore and the axis of which is substantially material in said bore to now from under said plunger sidewardly and upwardly along the sides of the plunger to fill the space between said plunger and the walls of said bore, holding said machine element against said bed during movement of said v plunger in the manner described and independently of the force applied to said plunger, causing the material to harden, and thereafter withdraw- 

